The present invention relates to production of interactive video.
Interactive television systems allow the viewer to interact with the program. For example, an interactive broadcast of a sporting event may allow the user to retrieve additional information about a particular player or to participate in an interactive game related to the sporting event. These actions are performed using a computer associated with the user's television set. Most typically, the computer is incorporated in a “set-top box.” The interactive program stream includes conventional video signals which are displayed on the television set and also includes data specifying the actions to be performed by the user's computer in response to user input. For example, the video stream for a sporting event may include conventional video graphics indicating the name of a particular player together with a picture of the player. The program-defining data is provided in a form commonly referred to as an “interactive trigger” according to a standard protocol. The interactive triggers may include a uniform resource locator or “URL” identifying a web page or other content available on the Internet; and data identifying a script and providing parameters for the script including coordinate data specifying a “hot spot” or portion of the television screen and actions to be taken when the viewer positions a cursor on the hot spot and provides input such as a mouse or remote control click. In the example of a sporting event, the hot spot may be defined as the area of the screen encompassing the player's name as displayed by the conventional video graphics and the URL, script and parameters may be selected so that when the user clicks on this hot spot, the user's computer will retrieve additional information about the player from the page designated by the URL and will display that information on the screen along with the conventional video.
The interactive triggers must be coordinated with the conventional video graphics. For example, if the video graphics are displaying the name of player “John Jones” in the lower left corner of the screen during one portion of the program, the triggers supplied to the viewer's unit should define the hot spot in the lower left corner of the screen and should instruct the user's unit to access data about John Jones in response to a click on the hot spot. If the video graphics displayed at another time in the program display the name of player “Sam Smith” in the upper right hand portion of the screen, the trigger supplied during that portion of the program should instruct the viewer's unit to define a hot spot in the upper right corner of the screen and should instruct the viewer's unit to retrieve data about player Sam Smith in response to a click on that hot spot.
The interactive video stream includes two separate components: the video graphics data which defines an image viewable on the television set and the interactive triggers which are intelligible to the computer in the viewer's unit. The triggers and video graphics data are supplied in a data stream according to a standard protocol corresponding to the protocol used by the viewer's unit. One such protocol is described in the enhanced content specification published by the Advanced Television Enhancement Forum and commonly referred to as the “ATVEF” specification, published by ATVEF Licensing LLC of El Dorado Springs, Colo., USA, the disclosure of which is hereby incorporated by reference herein. For example, in one format according to the ATVEF Specification, triggers can be carried in triggers can be carried as teletext characters during the vertical blanking interval of an NTSC (conventional United States television signal) video stream.
Production of interactive television programs has required considerable effort heretofore to incorporate the appropriate triggers into the video stream. Moreover, the procedures for incorporating triggers have not been suited to normal television production practice. A typical video production facility includes numerous sources of video graphics as, for example, video feeds from numerous cameras capturing live action, one or more tape or disc players, and one or more character generators. One example of such a character generator is sold under the registered trademark iNFiNiT! by the Chyron Corporation of Melville, N.Y., the assignee of the present application, and is described in publications such as the iNFiNiT! Family Operation Manual, Chyron Pub. No. 2A01976, Rev. D, March 1999, the disclosure of which is hereby incorporated by reference herein. Such character generators are well-known in the art. Each character generator typically has one or more graphic supply channels. The character generator can retrieve a computer file and generate a video signal incorporating a graphic element as specified in the file. For example, the graphic data in the file may include text and data specifying the format of the text as, for example, the type face and size as well as template data specifying a region of the video screen to be occupied by the text.
Typically, all of the various graphic sources in the production facility are linked to input ports of a video switch. The video switch also has an output port. The video switch can be manually or automatically operated to select a set of graphic sources and incorporate the video graphic signals from the various sources into the output signal. In a live broadcast environment, a human director actuates the video switch to display the most appropriate graphics. For example, while broadcasting a sporting event, where players Smith and Jones are on the field, the director may actuate the switch to display output from one or more of the cameras covering the action. During this time, the character generator may be “cued” to generate graphics with the name of player Smith on one channel and the name of player Jones on the other channel, but these graphics are not included in the output signal from the switch. When player Jones scores a goal, the human director may decide to add the graphics showing his name superimposed on the image captured by the camera. The director does this by actuating the switch to add the graphics supply channel displaying that graphic to the set of video graphics included in the output signal. On the other hand, if player Smith scores a goal, the director actuates the switch to include the graphics supply channel carrying the graphic with player Smith's name. These procedures are widely used in television production. However, these procedures do not lend themselves to incorporation of interactive triggers in the output signal. Indeed, early attempts to include interactive triggers in a live broadcast have required a human operator to watch the output signal to deduce what graphic is being displayed and actuate a computer storing various triggers to forward the correct trigger to an device known as an “inserter” linked to the output port of the switch so that the inserter will insert the triggers into the output signal at the correct time. This requires an additional operator and, of course, introduces opportunities for errors.
Thus, despite all of the efforts in the art toward development of interactive television, there has remained a need heretofore for improvement in the apparatus and methods used to embed interactive triggers in a video stream. In particular, there have been needs for apparatus and methods which are compatible with conventional broadcast industry practices and which can incorporate the appropriate triggers into the video streams without significant additional effort on the part of the operator during the production session.